Parodia, native to the uplands of Argentina, Peru, Bolivia, Brazil, Colombia and Uruguay. Notocactus, with the center of the genus in Brazil and Argentina, but with members throughout the Eastern side of the Andes.
Euphorbia is one of the largest of the succulent plant families. The genus Euphorbia is found throughout the tropics and semi tropics around the world, with some members of the family growing well into temperate regions.
From Mexico and Southern US. Usually having heavy spination and relatively small flowers, the fruits are copiously woolly. Includes the "Golden Barrel Cactus".
Most of these are from Mexico, although they occur in the southern United States and into South America.
Four related genera native to South Africa that grow in a Mediterranean like environment with winter-rainfall; similar to that of Southern California.